Starting safety switch



Oct- 13, 1925- O. 5. JENNINGS STARTING SAFETY swrrcu Filed April 7, 1920 2 Sheets-Sheet l INVENTOR 0/1'Ver .5 Jammy:

WITNESSES 52,411:

ATTORNEY Oct 13, 1925'- O. 5. JENNINGS STARTING sin-"m1! swn'cu 2 shoeta she'et 2 rum April '7, 192

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ATT'ORNEY Patented Oct. 13, 1925.

UNITED STATES 1,557,056 PATENT OFFICE.

O'LIVER 8. JENNINGS, OF BROOKLYN, NEW YORK, ASSIGNOR TO WESTINGHOUSE ELEC- TRIO & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

STARTING SAFETY SWITCH.

Application filed April 7, 1920. Serial No. 371,926.

To all whom it may concern:

Be it known that I, OLIVER S. JENNINGS, a citizen of the United States, and a resident of Brooklyn, in the county of Queens and State of New York, have invented a new and useful Improvement in Starting Safety Switches, of which the following is a specification.

My invention-relates toswitch boxes and particularly to safety switch boxes.

One object of my invention is to provide a safety switch box that. shall have a snap switch therein actuated by a reciprocating lever arm showing the position of the switch, a latch for the door thereof that shall be so interlocked with the switchv that the latch cannot be opened when the switch is closed and a second interlock that shall. prevent the switch from being closed when the door is opened and the door fmm being opened when the switch is closed.

Another object of my invention is to pro vide'a safety switch box, of the above indicated character, that shall have protective devices for actuating the switch uporran occurrence of low voltage, or of an overload, thereon.

' A further object of my invention is to provide a safety switch box, of the above. indicated character, that shall be simple and inexpensive to construct and effective in its operation.

In practisin my invention, I provide a spring-actuate is disposedv in a box or casing having a door to the fuse compartment thereof. The switch is provided with an oscillating lever arm that extends outside the box for actuating the same, and the door is provided with a latch for holding the same in its closed position. A lever is associated with the switch and is so interlocked with the latch that the latter cannot be operated to permit opening the door when the switch is in its closed position and an interlock is so disposed with respect to the switch that it cannot be turned to its closed position when the door is open. For overload and low-voltage protection to the apparatus to be controlled by the switch, I provide a plurality of overload relays that are adaptedto fit into ordinary fuse clips, and a low-voltage tripping device that i'sactuated upon an occurrence of a low-voltage in the circuit.

Cepending application, Serial No. 281,912,

rotatable snap switch that' filed Mar. 11, 1919, by H. G. Baxter, and assigned to the Krantz Manufacturing Company Incorporated, discloses a switch box with a door and a switch there-in with interlocking means for precluding the actuation of either the door or the switch except under predetermined conditions.

Copending application, Serial N 0. 308,723,

filed by Henry D.'James, July-5,-1919 and end view, partially in section and partially in elevation, of the box-shown in Fig. 1; Fig. 4 is a front elevational view of the low-voltage device shownin Fig. 1; and Fig. is a diagrammatic View showing the connections of the Winding of the low-voltage device to the overload relays.

A switch box 1 is constructed of metal or other fireproof material and is provided with a door 2 covering an opening in a portion. thereof adjacent a plurality of prot6Ct1W3 relays 3 located therein. An insulating panel board or base 4 is disposedin the box 1 and is adapted to support the stationary contact members 5 and 6 and the relay terminals 7 and 8. The insulating based is also adapted to support standards 9 and 10 upon which is mounted the rotatable member 11 of the switch.- A handle 12 extends outwardly from one side of the box for the purpose of actuating the switch.

Bridging contact members 13 are mounted on the rotatable member 11 and are adapted to engage the stationary contact members 5 and 6. A disc member 14 is also rigidly mounted on the member 11, and a shaft 15, that is attachedto the handle 12, is disposed within the rotatable member 11 and is relatively movable with respect thereto. A lever arm 16 is rigidly mounted on the projecting end of the shaft and is provided with a projection 17 that is adapted to actuate, under predetermined conditions, two latch members 18 and 19 that are pivoted to the bracket 10. A spring 20 is disposed around a portion of the rod 15,

' engagin 22 with the pin 24".

and 19, respectively, for the purpose of holding the switch member 11 in its several positions, the latch 19 being shown in Fig. 3 as the notch 22" for retaining the switch b ades 13 in closed position, and the latch 18 being shown in Fig. 4 as engaging the notch 22 for retaining the switch blades in open position. A spring 23 is disposed between the latches 18 and 19 for the purpose of retaining the same in engagement with the notches 22 and 22, respectively, on the periphery of the disc 14. A plurality of lateral projections or pins are mounted on .the disc 14, of which one pin 24 is straddled by the respective ends 20 and 20 of the spring 20, and two other pins 24 are adapted to be engaged by the pro ect on 17 to positively actuate the rotatable member 11 when the tension force alone, of the s ring 20, is insuflicient to withdraw the b ades 13 from their respective contact members. A stationary pin 24" is mounted on the bracket 10 adjacent the periphery of the disc 14 and engages the ends of the notch 22 and serves to limit the movement of the disc 14.

Referring to Fig. 3, it will be seen from the foregoing that, when the operating handle 12 is turned counter-clockwise, the p ro-. jection 17 will bias the end 20 of the spring 20 toward the left and put the end 20 under tension against the pin 24 on the disc 14, tending to turn the disc and switch counter-clockwise. Rotation of the d1sc 14 and-the switch shaft 11 is, however, prevented by reason of the engagement of the latch 19 with the left-hand end of the notch 22 until the projection 17 dis laces the latch 19 sufliciently to permit the eft end of the notch 22 to clear the latch. When the latch 19 is moved clear of the notch, the end 20" of the spring 20 will move the pin 24, the disc 14 and the switch shaft 11 to open position with the snap action, the movement, however, bein limited by reason of the engagement of t e right-hand end of the notch Just prior to the final movement of the disc 14 to open position, the rlght-hand'end of the notch 22' is moved into registry with the stop seat 18 and the spring 23 then snaps the latch 19 into retaining engagement with the right-hand end of the notch 22 and thereby prevents reverse movement of the disc until the latch 18 has been displaced to the right by reason of the engagement of the projection 17 therewith whenthe operating handle has been moved to closed position.

When the operating lever is turned in a clockwise direction to closed position, the end 20 of the spring 20 is biased to the right while the end 20 of the spring tends to move the pin 24 and disc 14 in a clockwise direction. This movement takes place after the dischas been released by reason of releasing movement'of the latch 18 by the projection 17. The stop 24 limits the closing movement of the disc 14 by reason of its engagement with the left end of the notch 22. The latch 19 then serves to prevent reverse movement of the disc 14 until it has again been displaced clear of the left end of the notch 22 by the projection 17. Should the switch members 13 stick within the contact members in such manner that the spring 20 fails to withdrawn them, the positive engagement of the projection 17 with either of the pins 24 will cause positive starting movement of the switch blades.

A second spring 25 is also dis osed on a portion of the shaft 15. One en 25 of the spring 25 is secured to a standard 10 and the other end 25" is secured to a rojection 26 on the lever arm 16. The pro ection 26 is adapted to be maintained in a predetermined closed position by a latching member 27, the actuation of which is controlled by a low-voltage device 28.

The low-voltage device 28 comprises a stationary magnetizable core member 29, a pivoted movable armature member 30 and a winding h31 for energizing the core member 29. e latching member 27 is secured ,to, or is integral with, the movable armature member 30 and is adapted to release the projection 26 when the winding 31 is sufliciently deenergized or when the handle 12 is forcibly moved to its oil osition. A pivoted movable lever 32 is a apted to be actuated by a cam member 33 that is mounted on the shaft 15 and is so disposed with respect to a pivoted interlocking member 34 carried by the cover as to actuate the same, under predetermined conditions, for controlling the movement of a latch member 35 carried by the door 2.

As shown in ing member 34 comprises a flat metal strip having inwardly bent flanges 34 and 34" and is pivoted to the cover at a point intermediate its ends. The flange 34" is adapted to abutthe free end of a metal interlock strip 35 that is slidably secured to the inner side of the door 2 and which extends into the housing 35 of the latch 35, the enclosed end abutting the latch handle and being movable therewith. The end i 34' engages the free end of the lever 32 and is held thereby, when the switch is closed, in such position that the flange 34" Figs. 2 and 3, the interlockprevents movement ofi the strip 35 and the latch When the switch is moved to open position, the cam 33 permits the lever 32 to move counter-clockwise and thereby so release the latch35 that it may be opened.

A disc member 36 is mounted on the rotatable member 11 and has an edge thereof bent back to form an arcuate flange 37 that is concentric with the hinge of the door 2 when the switch has been turned to the off position. An interlocking member 38 is secured to the door 2 and is so actuated by a spring 39, when the latch 35 is released, that the door 2 is yieldingly held open. The interlocking member 38 is provided with two projections 40 and 41 that are adapted to straddle the flange 37, when the switch is open and the door is moved to open position, to preclude any actuation of the switch when the door 2 is in any position intermediate open and closed positions. A lip 42 on the disc member 36 is adapted to limit the opening movement of the door by limiting the movement of the interlocking member 38 by reason of its engagement with the lip when the door is in open position. -When the switch is closed, the voltage between two conductors of the circuit shown in Fig. 5, to which the switch is connected, will be sufiieient to energize the winding 31 of the low-voltage device, if normal conditions obtain therein. During the closure of the switch by means of the action of the spring 20, the spring 25 is tensioned for opening movement by means of the shaft 15 and the handle 12, and the rojection 26 on the lever arm 16 is brought mto position to be engaged by the latch 27 of the low-voltage device 28. The cireuit of the winding 31 of the low-voltage device is completed through the overload relays 3 and is adapted to be opened, upon the actuation of the relays, by reason of an overload on the circuit to be protected.

v The winding 31 may, therefore, be so deenergized, by reason of low-voltage in the circuit or by reason of overload therein as to permit the armature member 30 to so actuate the latch 27 as to release the projection 26 of the lever arm 16. Upon the release of the projection 26, the tension of the spring 25 is sufiicient to actuate the rotatable member 11 and thereby open the switch.

hen the switchis in its closed position, the lever 32 is so maintained in its extreme position by means of the cam 33, as to prevent sufiicient movement of the interlockingmember 34 to permit the latch 35. to be actuated to open the door 2. The disc 36. moreover, is in such position that the projections 40 and 41 of the interlock ing member 38 cannot engage the same and, also, are so prevented from moving, by the lip 42 on the cam member 36, as to further prevent the opening of the door2 when the switch is closed. When the switch is open, the cam member 33 is in such position as to permit the lever 32 to be sufiiciently moved to permit a correspondingly sufficient movement of the member 34 for the purpose of providing space wherein the latch 35 may be moved to open the 'door. When the switch is open, the disc member 36 is in such position as to permit sliding engagement between the arcuate flange 37 of the cam member 36 and the projections 40 and 41 of the interlocking member 38, and, consequently, to permit the opening of the door 2. \Vhen the door 2 is open, engagement of the interlocking member 38 with the cam member 36 precludes any actuation of the switch, until the door 2 is reclosed. cam member 36 is released and the switch may be closed.

As shown in Fig. 5, the circuit of the winding 31 of the low-voltage device 28 may be opened upon the actuation of either one or of both relays 3 by reason of an overload thereon. Similarly, a low voltage between the two conductors, across which the low-voltage winding 31 is connected, will so sufficiently d e-energize the core member 29 as to permit the release thereby of the arma ture member 30. The releasing of the armature member 30 so actuates the latch 27 as to release the projection 26 hat restrains the spring 25. The spring 5, when released, immediately actuates the movable member 11 toopen the switch.

Although I have shown a preferred form of switch embodying my invention, I do not limit it to the structure shown, since various modifications may be made therein, without departing from the spirit and scope of my invention as set forth in the appended claims.

11 claim as my invention:

1. The combination with a. casing having a door therefor, of a snap switch, latching means for maintainingthe switch in the desired position, means operable from without the casing and responsive to low voltage and to overload for actuating the latching means, and interlocking means for precluding any operation of the switch when the door is open and for precluding the opening of the door when the switch is closed.

2. The combination with a casing having a door therefor, of a snap switch, latching means for maintaining the switch in the desired position, means operable from without the casing for actuating the latching means to permit the actuating of the "switch, aspring for actuating the switch, and means responsive to overload and to low voltage for controlling the spring.

3. The combination with a casing having a door therefor, of a switch interlock with Vhen the door 2 is reclosed, the

the door and operable from without the easing, latching means for maintaining the switch in the desired position, a cam member for actuating the latching means, resilient means for actuating the cam member and means responsive to overload and to low-voltage for controlling the resilient means.

4. The combination with a casing having a snap switch therein, of means for actuating the switch and indicating the position thereof extending through the casing and having a lost-motion connection with the switch, a latching means for maintaining the switch in the desired position, means for releasing the latching means and means responsive to overload and to low-voltage for controlling the switch actuating means.

5. In a safety switch boir having a door thereto, the combination with a switch and actuating -means therefor, of means for mamta-inlng the actuatlng means in a predetermined position, low voltage means for releasing the actuating means, automatically resetting overload'means for actuating the low-voltage means and interlockin means for precluding the actuation of t e door when the switch is in its closed position.

6. In a safety switch box having a door thereto, the combination with a switch and actuating means therefor, of means for maintaining the actuating means in a predetermined position, low-voltage means for releasingthe actuating means, automatically resetting overload means for actuating the low-voltage means and interlockin means for precluding the actuation of t e door when the switch is in its closed position and for precluding the actuation of the switch when the door is open. I

J In testimony, whereof, I have hereunto subscribed my name this twentieth day of March, 1920.

OLIVER S. JENNINGS. 

